docs: def pkcs7_unpad(buf):
      # type: (bytes) -> bytes
      """Removes PKCS7 padding a decrypted object
      :param bytes buf: buffer to remove padding
      :rtype: bytes
      :return: buffer without PKCS7_PADDING
      """
      unpadder = cryptography.hazmat.primitives.padding.PKCS7(
          cryptography.hazmat.primitives.ciphers.
          algorithms.AES.block_size).unpadder()
      return unpadder.update(buf) + unpadder.finalize()